Mine don't like fingernails, they try to pull mine off! They also like to pull hairs off my arm while I'm working, and see how big of a whole they can dig in my skin before I freak. I figured out that if I put one of those aquacear powerhead prefilters in the tank with a cube of mysis they leave me alone and try to get the mysis instead, or I just make my hand like a claw and chase em around for a while so they are scared of me until they forget then the cycle starts again.
For feeding, mine go after flake frozen or whatever they can find on the rock.